The ZGN_BUTTONPRESSED notification message is sent when the user has clicked on a cell having the button data type. The parent window of the ZeeGrid control receives this notification message through the WM_COMMAND message.
ZGN_BUTTONPRESSED
idZeeGrid = (int) LOWORD(wParam); //identifier of the ZeeGrid control
hwndZeeGrid = (HWND) lParam; //handle to the ZeeGrid control